TAKE AWAY the ARMOR

Actor Robert Downey Jr. was looking at the opportunity of a lifetime. He'd just landed the role of comic book superhero Tony Stark, the billionaire genius also known as Iron Man.

Stark is not your cookie-cutter superhero. He wasn't born with supernatural powers. He is flawed, gritty, intense — driven. Just ask Captain America.

In an epic movie scene, Captain America confronts Tony Stark. Taking one stalking, provoking step at a time, Captain America circles Stark, spitting out a question meant to expose Stark's inferiority.

"Big man in a suit of armor. Take that off, what are you?"

Stark doesn't miss a beat and doesn't even bother to turn his head to look at Captain America before answering.

"Genius, billionaire, playboy, philanthropist."

Those four words not only summed up the man, but also summed up the herculean task Robert Downey Jr. had before him.

Downey had to accomplish nothing less than making Tony Stark real. And that meant embodying those four words: genius, billionaire, playboy, philanthropist.

Sitting across from Iron Man director Jon Favreau, Downey discussed the role. He needed to understand Stark's character deeply, answering questions like what made Tony Stark tick, what drove his ambitions, what kind of genius could transform fantasy into reality. Because if you understand the character, then you can become him, and that's how you bring Tony Stark to life.

Downey was struck by an idea. He wanted to hang out with a real-life Tony Stark.

And he had someone in mind. One man whose personality and life actually epitomized the heart and soul of Tony Stark's character, with all the trappings of Stark's supersized success. If Downy could spend time with this man, study him, try to get in his head, well then, Downey could nail the role.

That man was Elon Musk.

At thirty-five years old, Elon had already amassed a fortune and was well on his way to becoming one of the most powerful people in the world. With companies like PayPal, Tesla, and SpaceX, he pushed technology to the limit until he forced innovation and breakthrough, making his mark on three of the biggest industries that exist: banking, automobiles, and space. His ambitious ideas were so far-out that people often laughed at him, until they didn't — usually because he'd accomplished the impossible.

In 2007, Robert Downey Jr. gave Elon a call and soon found himself walking around SpaceX headquarters with Elon himself — observing, talking, and picking Elon's brain. That time allowed Downey to perfect the role.

That said, there was a major divergence between Elon and the comic book character. Tony Stark's script came with a slick backstory: Child prodigy and heir apparent of famed entrepreneur accomplishes one incredible feat after another and then takes the helm of his father's company and pushes it to the next level and beyond.

Elon's backstory was far from slick. His childhood was dark, painful, and brutal. Elon had to endure both emotional torment at home and physical attacks at school. As a bullied schoolboy in Pretoria, South Africa, he was not an heir apparent. He was not a media darling in waiting. No, Elon was simply trying to survive.

NAME: Elon Reeve Musk

NICKNAMES: Genius Boy, Muskrat

DATE OF BIRTH: June 28, 1971

PLACE: Pretoria, South Africa

FIRST COMPUTER: Commodore VIC-20, at age 10

BOOKSHELF:The Hitchhiker's Guide to the Galaxy, by Douglas Adams, and Isaac Asimov's Foundation series.

GAME SHELF: Dungeons & Dragons

DAYDREAMS AND NIGHTMARES

As a little boy in South Africa, it was obvious from the time Elon could speak and toddle around that he was different. Elon's mom, Maye Musk, recognized her son's intelligence straightaway.

"He seemed to understand things quicker than other kids," she said.

But she noticed something else, too — something about Elon's behavior that concerned her. Elon would suddenly stare off in the distance, falling into a daydream so deep, so trancelike, that no one could get his attention. It could happen mid-conversation or in the middle of a busy room. His mother was worried. Did Elon have a massive hearing loss?

Shuffling him off to doctor after doctor, Maye tried to get to the bottom of it. The doctors saw it too. He sometimes seemed lost in another world that no one could penetrate.

Elon endured test after test. Finally, his doctors scheduled him for surgery. The plan was to remove his adenoids and hope Elon would hear better.

But the surgery had no impact at all. That's when they discovered his hearing was actually fine. It was his mind. Elon was simply so deep in thought, so focused on his ideas, immersed in every detail, that he detached from the rest of the world.

It was as if a movie was playing out before his eyes, allowing Elon to visually puzzle out a problem. Like daydreaming on steroids, he could not only see ideas but run virtual tests on them too.

"It seems as though the part of the brain that's usually reserved for visual processing — the part that is used to process images coming in from my eyes — gets taken over by internal thought processes," Elon explained to biographer Ashlee Vance. "I can't do this as much now because there are so many things demanding my attention but, as a kid, it happened a lot. That large part of your brain that's used to handle incoming images gets used for internal thinking."

That was not the only personality trait of Elon's that stood out from an early age. A penchant for breaking rules and breaking them boldly — with commitment, drive, and flair — landed six-year-old Elon in some pretty hot water with his mother.

It all started when Elon's mom grounded him. She made his punishment perfectly clear: Elon would not be allowed to go to his cousin's birthday party.

And Elon's reaction was also perfectly clear. Stay at home? When his younger brother and sister were going to the party? No way. Absolutely not.

Mind churning, Elon realized he needed a plan to get around the punishment.

Wait — his bike! He could ride his bike there. Elon let his mother know in no uncertain terms that he would most certainly be at the party. He didn't need her to drive him there. He would ride his bike — all by himself.

Elon recounted this story in an auditorium full of people at the Computer History Museum. The crowd hung on his every word as he explained that telling his mother was a critical mistake. Because as soon as he divulged his plan, his mother looked at her...